Have you been hearing about the use of Breast Ultrasound as a way to screen for breast cancer? There has been quite a bit of discussion on the news about this topic, recently, so I would like to take a moment to discuss why and when to use Breast Ultrasound as part of your breast health practices.

Screening mammography is the first, most important step in early detection of breast cancers because it can show changes in the breast years before you or your physician can feel them. Calcifications, which can be a sign of a very early pre-invasive breast cancer, can only be seen by mammography. If a problem is found on a screening mammogram or an area of clinical concern is present, a diagnostic mammogram is used to evaluate these findings.

Breast ultrasound can be the next step in evaluating a lump or mass. Ultrasound imaging can help to determine if a lump is solid (which may be a cancerous or non-cancerous tumor) or fluid-filled (i.e., a benign cyst). If a lump is found to be a cyst on ultrasound, nothing more is usually done. If it is determined not to be a cyst, but is a solid mass, biopsy is often recommended.

Ultrasound is also very useful in detecting lumps in patients with dense breasts. In breasts that are dense, meaning there is a lot of glandular tissue and less fat, many cancers can be hard to see on mammography. Using a combination of mammography and ultrasound as a screening method may result in earlier and more frequent detection of breast cancer. Usually, dense breasts are more commonly found in women under 50 years of age, but post menopausal women on hormones can also have very dense glandular tissue.

A new study of 2,809 women with non-fatty breasts showed screening with mammography alone detected 8 cancers per 1000 women screened. Screening with ultrasound alone detected 4 cancers per 1000 women screened. Screening with mammography and ultrasound detected 12.4 cancers per 1000 women screened so another 4 cancers per 1000 women screened were found on ultrasound that could not be seen on mammography alone.

The downside to screening with ultrasound, according to the author of the study, is that ultrasound finds non-cancerous lesions that can be suspicious and have to be biopsied, leading to a lot of falsely positive biopsies. This is definitely true if the ultrasound is performed by an inexperienced observer. However, in experienced hands, it is an extremely helpful examination.

I have been screening with ultrasound for years and find it an extremely helpful exam on patients with non-fatty breast tissue. For every three suspicious ultrasound masses I biopsy, I find on average one cancer, which is the expected positive biopsy rate using mammography as a screening tool.

A three-year study conducted by researchers at Baystate Health in Springfield, MA, found that a negative mammogram and ultrasound means there is only a 2% chance of missing a breast cancer. This compares favorably with a breast MRI in high-risk women, which if negative, only misses cancer 1% of the time. The problem with MRI, at this time, is there are so many false positives, which will lead to unnecessary biopsies. This is a criticism also of screening breast ultrasound in inexperienced hands. Undoubtedly, as experience with breast MRI and screening ultrasound improves, false positive rates will decrease.

Please let us know if you have any questions about Breast Ultrasound.

Best regards,

Belinda Barclay-White, MD
www.azbreastnet.com